Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 201940
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
340 PM EDT SUN JUL 20 2014

.SYNOPSIS...
ISSUED AT 337 PM EDT SUN JUL 20 2014

SOUTHERLY WINDS WILL SLOWLY INCREASE OVER THE NEXT 24
HOURS...ALLOWING WARMER AND INCREASINGLY MORE HUMID AIR TO MOVE
INTO THE REGION. HIGH TEMPERATURES ARE EXPECTED IN THE LOW TO MID
80S ACROSS THE REGION ON MONDAY WITH HIGHS NEAR 90 ON TUESDAY.
LOWS TONIGHT WILL DROP INTO THE UPPER 50S TO LOWER 60S. THE NEXT
CHANCE FOR RAIN WILL OCCUR WITH A COLD FRONT TUESDAY NIGHT INTO
WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 337 PM EDT SUN JUL 20 2014

RIDGE AXIS WILL SHIFT JUST A BIT EAST OVER THE NEXT 24 HOURS. THIS
WILL BE SUFFICIENT TO HOLD OFF ON ANY PRECIP CHANCES THROUGH THE
PERIOD BUT WILL STILL ALLOW THE MAIN SURGE OF WARMER AIR TO BEGIN.
WITH WARMER AFTERNOON TEMPERATURES TODAY...OVERNIGHT LOWS SHOULD
DROP INTO THE UPR 50S TO LOWER 60S IN MOST LOCATIONS. COULD BE SOME
PATCHY FOG IN SOME LOCATIONS...BUT WITH MORE EXTENSIVE SUNSHINE
EARLIER TODAY ALLOWING FOR SOME "DRYING" OF THE BOUNDARY
LAYER...THINK THERE WILL BE LESS COVERAGE AND WILL NOT PLACE IN
GRIDS.

INCREASE IN MID LEVEL WARM AIR WILL ALLOW FOR LESS IN THE WAY OF CU
DEVELOPMENT ON MONDAY DESPITE INCREASING MOISTURE. STILL EXPECTING
SCT CU TO POP TO LEAD TO MOSTLY SUNNY/PARTLY CLOUDY SETUP. HIGH
TEMPS SHOULD CLIMB A FEW DEGREES HIGHER THAN TODAY INTO THE MID 80S.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 337 PM EDT SUN JUL 20 2014

INCREASING HEAT FOLLOWED BY CONVECTIVE CHANCES TUESDAY NIGHT INTO
WEDNESDAY WILL CONTINUE TO BE THE PRIMARY FORECAST CONCERNS FOR THE
LONG TERM.

MID/UPPER LEVEL RIDGE AXIS WILL BE POSITIONED ACROSS THE WESTERN
GREAT LAKES MONDAY NIGHT WITH A SERIES OF SHORT WAVES IN ASSOCIATION
WITH CUT-OFF PV ANOMALY ACROSS SOUTHWEST CONUS EXPECTED TO SLIGHTLY
DAMPEN UPPER RIDGE ACROSS CENTRAL CONUS. MAIN ITEM OF INTEREST FOR
TUESDAY WILL BE THE INCREASING HEAT. DAMPENING OF UPPER LEVEL
RIDGING WILL ALLOW FOR EASTWARD MIGRATION OF LOW LEVEL THERMAL RIDGE
INTO THE LOCAL AREA LATE MONDAY NIGHT INTO TUESDAY. STRONG LOW LEVEL
WAA SHOULD LIMIT MIXING HEIGHTS TO AROUND 900 HPA OR SO. MIXING TO
THIS LEVEL COMBINED WITH CONSENSUS LOW LEVEL THERMAL PROGS GENERALLY
SUPPORT HIGHS IN THE UPPER 80S TO LOWER 90S. LINGERING AXIS OF
RELATIVELY DRIER LOW LEVEL AIR SHOULD STILL RESIDE FROM MID MS
VALLEY INTO THE SOUTHERN GREAT LAKES REGION TO BEGIN THE
PERIOD...WHICH IS A REMNANT OF THE EXTENDED PERIOD OF SUBSIDENCE
LOCAL AREA HAS BEEN INFLUENCED BY. SOUTHERLY LOW LEVEL FLOW SLOWLY
RAMPS UP FOR TUESDAY...DRAWING IN SOME SLIGHTLY BETTER LOW LEVEL
MOISTURE FROM THE LOWER OHIO VALLEY. MORE LIMITED MIXING HEIGHTS MAY
TEND TO DISCOURAGE SIGNIFICANT AFTERNOON DEW POINT DROPS...AND STILL
FEEL THAT MID TO UPPER 60S DEW POINTS ARE REASONABLE GIVEN THE
COMPETING FACTORS OF WEAK MOISTURE ADVECTION/DIURNAL MIXING. THE
ABOVE SCENARIO SHOULD PRODUCE AFTERNOON HEAT INDICES IN THE LOWER TO
MID 90S. WILL MAINTAIN DRY FORECAST THROUGH TUESDAY WITH WARMISH MID
LEVELS AND RELATIVELY MODEST MOISTURE PROFILES PROVIDING INHIBITION
FOR SFC/NEAR SFC BASED PARCELS.

PRIMARY MID LEVEL IMPULSE ASSOCIATED WITH SOUTHWEST CONUS PV ANOMALY
SHOULD REACH INTO THE UPPER MS VALLEY LATE TUESDAY NIGHT. NOCTURNAL
STORMS ARE STILL EXPECTED ACROSS THE UPPER MIDWEST/WESTERN GREAT
LAKES TUESDAY NIGHT WITH SOME POTENTIAL OF SHOWERS AND STORMS MAKING
IT INTO NORTHWEST PORTIONS OF THE AREA OVERNIGHT. OBVIOUSLY AT THIS
FORECAST DISTANCE PLENTY OF UNCERTAINTIES PERSIST IN REGARDS TO
UPSTREAM CONVECTION TUESDAY NIGHT...AND TRACK/STRENGTH OF ANY
CONVECTIVELY INDUCED VORTS. ORIENTATION OF BEST INSTABILITY AXIS
ALSO MAY TEND TO SUPPORT MORE OF AN UPWIND PROPAGATION TO THIS
POTENTIAL CONVECTION AS OPPOSED TO SOUTHEAST INTO LOCAL AREA. FOR
THIS REASON...HAVE MAINTAINED CONSERVATIVE POPS IN THE LOW TO MID
CHANCE CATEGORY ACROSS NORTHWEST HALF LATE TUESDAY NIGHT.

MORE LIMITED INSTABILITY ACROSS LOCAL AREA MAY RESULT IN ANY
POTENTIAL OVERNIGHT CONVECTION UPSTREAM BEING IN DIMINISHING STATE
WEDNESDAY MORNING ACROSS THE AREA...WITH SOME POTENTIAL
REDEVELOPMENT ACROSS MAINLY SOUTHEAST HALF WEDNESDAY AFTERNOON.
TREND IN NUMERICAL GUIDANCE HAS BEEN TOWARD FASTER FRONTAL
PROGRESSION...AND HAVE CONTINUED TREND OF PAST SEVERAL FORECASTS IN
SPEEDING UP POP TIMING WHICH MAY NEED TO CONTINUED IN UPCOMING
FORECASTS. CURRENT INDICATIONS NOW SUGGEST BULK OF PRECIP MAY BE
SOUTHEAST OF THE AREA BY 00Z THURSDAY. SEVERE POTENTIAL STILL
APPEARS TO BE QUITE LOW GIVEN SOMEWHAT UNFAVORABLE DIURNAL TIMING TO
FRONT...AND OVERALL MARGINAL SHEAR PROFILES.

A PERIOD OF BELOW NORMAL TEMPS AND DRY CONDITIONS THEN EXPECTED FOR
THU-FRI...ALTHOUGH LOW LEVEL WAA AHEAD OF MORE AMPLIFIED TROUGH
PROGRESSING THROUGH WESTERN CONUS MEAN UPPER RIDGING MAY PROVIDE
NEXT CHANCE OF PRECIP FOR THE WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 213 PM EDT SUN JUL 20 2014

CU FIELD HAS EXPANDED ACROSS THE ENTIRE AREA. LAKE SHADOW WAS
CONFINED PRETTY CLOSE TO THE SHORE AT THIS TIME BUT SHOULD DRIFT
IN SLOWLY THE REMAINDER OF THE DAY. REGARDLESS...VFR CIGS THROUGH
THE PERIOD WITH LESS CU DEVELOPMENT AS STRONGER CAP BEGINS TO
SETTLE IN DURING THE AFTERNOON ON MONDAY. HAVE LEFT MENTION OF FOG
AT KSBN ALTHOUGH GIVEN MORE EXTENSIVE SUNSHINE EARLIER...BOUNDARY
LAYER HAS LIKELY MIXED OUT SOMEWHAT IN TERMS OF MOISTURE.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...MARSILI
AVIATION...FISHER


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